Genuine OEM HP OfficeJet R60 Ink and Supplies
The OfficeJet R60 uses HP 45 black alongside HP 23 tri-color, with all three color inks in that one color cartridge. The 45/23 combo covers both cartridge positions. A 45 twin pack instead gives you two black cartridges, so it serves a different need from the combo.
Toner Buzz carries genuine HP 45 and HP 23 ink as individual cartridges, the black twin pack, and the black-and-color combo. Choose the combo for both inks together, or the twin when black ink is the one you want to keep in reserve.